JPH07266563A - Liquid jet recording head - Google Patents

Abstract

PURPOSE:To eliminate crosstalks in a certain specific print area and a drive frequency and to make discharge performance uniform in a bubble-jet type ink jet multiple-nozzle array. CONSTITUTION:In a bubble-jet type liquid jet recording head of a multiple-nozzle array, the relation between the height ha of a liquid channel 14 and the height hb of a recording liquid chamber 16 is hb/ha>2 and the maximum printable area of a head is 6mm or over and 16mm or less or the drive frequency of a heating element 19 is 3.2kHz to 6.6kHz. Thus any cross talk between channels can be eliminated and discharge performance irregularities no longer occur between the center and the ends.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid jet recording head,
More specifically, it relates to the dimensions of the flow path and liquid chamber of the bubble jet head.

[0002]

2. Description of the Related Art The non-impact recording method has recently attracted interest in that noise generation during recording is negligibly small. Among them, the so-called inkjet recording method, which is capable of high-speed recording and is capable of recording on so-called plain paper without requiring a special fixing process, is an extremely powerful recording method, and various methods have been used so far. Was proposed, and some were improved and commercialized,
Some of them are still being put into practical use.

Such an ink jet recording method causes droplets of a recording liquid, so-called ink, to fly,
Recording is performed by adhering it to a recording member, and is roughly classified into several methods according to the method of generating the recording liquid droplets and the control method for controlling the flight direction of the generated recording liquid droplets. It

First, the first method is, for example, USP No. 3060429.
(Tele type method) disclosed in the specification, in which droplets of recording liquid are generated by electrostatic attraction, and the generated recording liquid droplets are subjected to electric field control according to a recording signal to perform recording. Recording is performed by selectively depositing recording liquid droplets on the member. This will be described in more detail. An electric field is applied between the nozzle and the acceleration electrode to eject uniformly charged droplets of the recording liquid from the nozzle, and the ejected droplets of the recording liquid are used as recording signals. Xy configured to be electrically controllable according to
Recording is performed by flying between the deflection electrodes and selectively adhering small droplets on the recording member by a change in the strength of the electric field.

The second method is a method (Sweet method) disclosed in, for example, USP No. 3596275, USP No. 3298030, etc., in which the charge amount is controlled by a continuous vibration generating method. Recording is performed on a recording member by generating small droplets of a liquid and causing the generated droplets whose charge amount is controlled to fly between deflection electrodes to which a uniform electric field is applied. . Specifically, the charging electrode configured so that the recording signal is applied before the orifice (ejection port) of the nozzle, which is a part of the recording head provided with the piezoelectric vibration element, is separated by a predetermined distance. And place
By applying an electric signal of a constant frequency to the piezoelectric vibrating element, the piezoelectric vibrating element is mechanically vibrated and a small droplet of the recording liquid is ejected from the ejection port. At this time, electric charges are electrostatically induced in the recording liquid droplets ejected by the charging electrodes, and the droplets are charged with an electric charge amount corresponding to the recording signal. The droplets of the recording liquid of which the charge amount is controlled are deflected according to the added charge amount when flying between the deflection electrodes to which a constant electric field is uniformly applied, and the droplets that bear the recording signal Only one is allowed to adhere to the recording member.

The third method is, for example, the method (Hertz method) disclosed in US Pat. No. 3,416,153, in which an electric field is applied between a nozzle and a ring-shaped charging electrode, and a recording liquid is generated by a continuous vibration generating method. This is a method of recording by generating and atomizing small droplets of. That is, in this method, the atomization state of the small droplet is controlled by modulating the electric field strength applied between the nozzle and the charging electrode according to the recording signal, and the gradation of the recorded image is produced and recording is performed.

The fourth method is, for example, the method (Stemme method) disclosed in US Pat. No. 3,747,120, and this method has a fundamentally different principle from the above-mentioned three methods. That is, in all of the three methods, the droplets of the recording liquid ejected from the nozzles are electrically controlled during the flight, and the droplets carrying the recording signal are selectively deposited on the recording member. On the other hand, the Stemme method is used to perform recording by ejecting and ejecting a small droplet of recording liquid from an ejection port according to a recording signal. In other words, the Stemme method applies an electrical recording signal to a piezoelectric vibrating element attached to a recording head having a discharge port for ejecting a recording liquid, and converts this electrical recording signal into mechanical vibration of the piezoelectric vibrating element. Instead, recording is performed by ejecting and ejecting a small droplet of the recording liquid from the ejection port according to the mechanical vibration and adhering it to the recording member.

These four conventional methods have their respective characteristics, but there are some points that can be solved in the other. That is, in the first to third methods, the direct energy for generating the droplet of the recording liquid is electric energy, and the deflection control of the droplet is electric field control. Therefore, the first method is simple in construction, but it requires high voltage to generate small droplets, and it is difficult to form the recording head with multiple nozzles. Therefore, the first method is not suitable for high-speed recording. The second method allows the recording head to have multiple nozzles and is suitable for high-speed recording, but it is complicated in structure, and it is difficult and difficult to electrically control recording liquid droplets. However, there is a problem in that

The third method has the feature that an image with excellent gradation can be recorded by atomizing recording liquid droplets, but on the other hand, it is difficult to control the atomized state, There are various problems such as fog being generated and it is difficult to use a multi-nozzle recording head, which is not suitable for high-speed recording.

The fourth method has relatively many advantages as compared with the first to third methods. That is, since the structure is simple and the recording liquid is discharged on-demand from the discharge port of the nozzle to perform recording, the droplets ejected and ejected as in the first to third methods are ejected. Medium, there is no need to collect small droplets that were not needed for image recording, and there is no need to use a conductive recording liquid as in the first and second methods, and it is not necessary to use a recording liquid substance. It has great advantages such as a high degree of freedom. On the other hand, on the other hand, it is difficult to form a multi-nozzle recording head because of problems in processing the recording head, miniaturization of a piezoelectric vibrating element having a desired resonance number, and the like. However, since the recording liquid droplets are ejected and ejected by the mechanical energy of mechanical vibration of the piezoelectric vibrating element, it is not suitable for high-speed recording.

Further, in Japanese Patent Application Laid-Open No. 48-9622 (corresponding to US Pat. No. 3,747,120), as a modification, instead of utilizing mechanical vibration energy by means such as the above-mentioned piezoelectric vibrating element, etc. The use of thermal energy is described. That is, the above-mentioned publication describes a so-called bubble jet liquid jet recording apparatus that uses a heating coil that directly heats a liquid in order to generate vapor that causes a pressure increase, as a pressure increasing means instead of a piezoelectric vibrating element. There is.

[0012] However, in the above publication, the heating coil serving as the pressure increasing means is energized to directly heat the liquid ink in the bag-shaped ink chamber (liquid chamber) having only one opening through which the liquid ink can come in and out. However, there is no suggestion as to how to heat in the case of continuously repeating the liquid discharge. In addition, since the position where the heating coil is provided is provided at the deepest part of the bag-shaped liquid chamber far away from the liquid ink supply path, the head structure is complicated and continuous at high speed. Not suitable for repeated use.

Further, from the technical contents described in the above publication, it is impossible to promptly form a ready state for the next liquid ejection after the liquid is ejected by generated heat which is practically important. As described above, the conventional method has advantages and disadvantages in terms of configuration, high-speed recording, multi-nozzle recording head, occurrence of satellite dots and occurrence of fog in recorded images. There was a constraint that it could only be applied.

Further, in Japanese Patent Application Laid-Open No. 55-132271, each of a predetermined number of working chambers communicating with a discharge port of the recording liquid and the recording liquid is supplied from the supply source to each of the working chambers. Has a relay chamber for forming a part of the relay chamber, and a communication port with the working chamber is provided on a wall surface of which the area is W, and the total area of these communication ports is A liquid jet recording apparatus has been proposed in which all working chambers are brought into contact with the relay chamber so that the value of W / S becomes 50 or more, where S is S.

FIG. 19 is a cross-sectional view of an essential part showing an example of an extreme case of the ink jet head as described above. As shown in the figure, the wall surface 1 of the relay chamber 1 has a long length l to increase the area W. , The ratio of the total area S of the communication port 2 to W / S ≧ 5
It is set to 0. In the ink jet head, the relationship between S and W, which is a factor for reducing the influence of crosstalk, is important, but more strictly speaking, the distance between the ejection orifices or the reflected pressure wave after one drop is ejected. It should be prescribed from the relationship such as. For example, as an extreme example, even if the relationship between the arrangement of the communication ports 2 and the wall surface 1 of the relay room is determined as shown in FIG. 19, W / S ≧ 5
It is possible to satisfy 0. However, it is difficult to reduce the crosstalk. The distance between ejection orifices, which is one of the factors for reducing crosstalk, is often determined from specifications such as print speed or print density, and is rarely determined from the viewpoint of preventing crosstalk. Therefore, it is desirable to take preventive measures due to other factors, that is, the relationship between reflected pressure waves and the like.

[0016]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and in particular, in a bubble jet type ink jet multi-nozzle array, in a certain specific printing area and at a driving frequency, crossing is performed. The purpose is to eliminate the talk and to make the ejection performance uniform.

[0017]

In order to achieve the above-mentioned object, the present invention communicates with a recording liquid chamber, contains a recording liquid introduced from the recording liquid chamber, and heats the recording liquid to generate bubbles. And a flow path provided with a thermal energy acting portion for generating a working force associated with an increase in the volume of the bubble, and an orifice for communicating with the flow path and discharging the recording liquid as a droplet by the working force. A liquid jet recording head comprising: a recording liquid chamber that communicates with the flow channel to introduce the recording liquid into the flow channel; and a unit that introduces the recording liquid into the recording liquid chamber, (1) When the maximum printable area is 6 mm or more and 16 mm or less, and the height of the flow path is ha and the height of the recording liquid chamber is hb, the relationship of hb / ha> 2 is satisfied, or (2) Driving the heating element The wave number and 3.2kHz~6.6kHz, and,
When the height of the flow path is ha and the height of the recording liquid chamber is hb, the relationship of hb / ha> 2 is satisfied.

[0018]

In the bubble jet type liquid jet recording head of the multi-nozzle array, the relationship between the height ha of the liquid flow path and the height hb of the recording liquid chamber is set to hb / ha> 2, and the head can print. The maximum area is 6 mm or more and 16 mm or less, or the driving frequency of the heating element is 3.2 kHz to 6.6 kHz.
By eliminating the crosstalk between each flow path,
Discharge performance does not vary between the center and the end.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view of an essential part for explaining an embodiment of the present invention, and FIG. 2 is a view for explaining the operation of a bubble jet head as an example of an ink jet head to which the present invention is applied. FIG. 3 is a perspective view showing an example of a bubble jet head, and FIG. 4 shows a lid substrate (FIG. 4 (a)) and a heating element substrate (FIG. 4 (b)) constituting the head shown in FIG. 5 is a perspective view of the lid substrate shown in FIG. 4 (a) as seen from the back side, wherein 11 is a lid substrate, 12 is a heating element substrate, and 13 is a recording liquid inlet. , 14 is an orifice, 15 is a flow path, 16 is a region for forming a liquid chamber, 17 is an individual
(Independent) electrode, 18 is a common electrode, 19 is a heating element (heater),
Reference numeral 20 is an ink, 21 is a bubble, and 22 is a flying ink droplet, and the present invention is applied to such a liquid jet recording head of the bubble jet type.

First, referring to FIG. 2, the ink jetting by the bubble jet will be described. (A) is a steady state, and the surface tension of the ink 20 and the external pressure are in equilibrium on the orifice surface. In (b), the heater 19 is heated and heated until the surface temperature of the heater 19 rapidly rises and boiling development occurs in the adjacent ink layer, and the minute bubbles 21 are scattered. (c) shows a state in which the adjacent ink layer that has been rapidly heated on the entire surface of the heater 19 is instantly vaporized to form a boiling film, and the bubble 21 is grown. At this time, the pressure in the nozzle rises by the amount of growth of the bubbles, the balance with the external pressure on the orifice surface is lost, and the ink column begins to grow from the orifice. (d) is a state in which bubbles have grown to the maximum, and the ink 20 corresponding to the volume of bubbles is pushed out from the orifice surface. At this time, no current is flowing through the heater 19, and the surface temperature of the heater 19 is decreasing. The maximum value of the volume of the bubble 21 is slightly delayed from the timing of applying the electric pulse. (e) shows a state in which the bubble 21 is cooled by ink or the like and starts to contract.
At the front end of the ink column, the ink column moves forward while maintaining the pushed speed, and at the rear end, ink contracts from the orifice surface into the nozzle due to the decrease of the nozzle internal pressure due to the contraction of the bubbles, and the ink column becomes constricted. . In (f), the bubble 21 is further contracted, the ink contacts the heater surface, and the heater surface is further rapidly cooled. On the orifice surface, the external pressure is higher than the internal pressure of the nozzle, so that a large meniscus enters the nozzle. The tip of the ink column becomes a droplet and flies in the direction of the recording paper at a speed of 5 to 10 m / sec. (g) is the process in which the ink is supplied (refilled) to the orifice again by the capillary phenomenon and returns to the state of (a),
The bubbles have disappeared completely.

Therefore, the present invention is to prevent crosstalk between orifices in the above-mentioned multi-array type head in the bubble jet type ink jet, and further, to prevent the crosstalk from the liquid chamber to the flow path. The recording liquid (ink) is quickly replenished, and variations in the replenishment speed in the vicinity of the center and both ends of the multi-array are reduced, thereby increasing the response frequency and variation in the ejection performance (of the multi-array). The difference between the center and both ends) is to be small.

In practical use of the multi-array head as described above, as is well known, there are crosstalks between orifices and variations in the speed at which the recording liquid (ink) is replenished to each flow path. The crosstalk can be almost solved by, for example, increasing the distance between the adjacent orifices (flow paths), but as a practical problem, the distance between the adjacent orifices is often determined from the specifications of the printer main body, and the crosstalk does not always occur. It is not always the desired distance for prevention. Therefore, a solution by another method is desired.

The present invention has been made in view of this point as described above, and if the relationship between the height of the liquid chamber and the height of the flow path is satisfied, the pressure wave that causes crosstalk will flow immediately adjacent to it. It is an experimental finding that it does not affect the road. On the other hand, a problem caused by variation in ink replenishment speed is that the ejection performance and response frequency vary due to different replenishment speeds near the center of the orifice and near both ends. In order to solve this, it is sufficient that the ink moving in the liquid chamber has less liquid resistance from the wall surfaces (bottom surface and ceiling) of the liquid chamber. For this purpose, the height to the ceiling must be a certain value or more. If you do
It has been experimentally revealed that the ink can move smoothly. Although the above-mentioned two points, that is, the crosstalk and the dispersion of the ejection performance are different problems, it is understood that the solution chamber height can be set to a certain value in order to solve them simultaneously.

FIG. 1 is a cross-sectional view taken along the line I--I of FIG. 3, where hb / ha> 2 when the height of the flow path 15 is ha and the height of the liquid chamber 16 is hb. By satisfying the relationship, the above two problems can be solved. Table 1 below shows the experimental results of the heads manufactured by changing the dimensions of ha and hb.

[0025]

[Table 1]

From the above results, it is set that hb / ha> 2 and the printable head width is 6 mm (48/8 =
6) or more and 16 mm (512 ÷ 32 = 16) or less, or
It can be seen that by selecting the maximum response frequency to 3.2 to 6.6 kHz, good droplet ejection can be performed without causing crosstalk or liquid supply shortage. Further, in the present invention, the number of orifices is large and the arrangement density is high (for example, 16
The maximum response frequency increases with the number of lines / mm or more), which is particularly effective for highly integrated heads.

FIG. 6 is a detailed view for explaining the structure of the bubble generating means using a heating resistor, in which 31 is a heating resistor, 32 is an electrode, 33 is a protective layer, and 34 is a power supply device. As useful materials for the heating resistor 31, for example, a mixture of tantalum-SiO ₂ , tantalum nitride, nichrome, silver-palladium alloy, silicon semiconductor,
Alternatively, there may be mentioned borides of metals such as hafnium, lanthanum, zirconium, titanium, tantalum, tungsten, molybdenum, niobium, chromium and vanadium.

Among the materials composing these heating resistors 31, metal borides can be mentioned as particularly excellent ones, of which hafnium boride has the most excellent characteristics. The order is zirconium boride, lanthanum boride, tantalum boride, vanadium boride, and niobium boride. The heating resistor 31 is made of the above material,
It can be formed using a technique such as electron beam evaporation or sputtering. The film thickness of the heating resistor 31 is determined according to the area, the material, the shape and size of the heat-acting portion, and the actual power consumption so that the amount of heat generated per unit time is as desired. However, in the usual case, it is 0.001 to 5 μm, preferably 0.01 to 1 μm.

As the material forming the electrode 32, many of the commonly used electrode materials are effectively used.
Specifically, for example, Al, Ag, Au, Pt, Cu or the like is used, and these are provided at a predetermined position and in a predetermined size, shape and thickness by a method such as vapor deposition.

The characteristic required of the protective layer 33 is that the heat generating resistor 31 is protected from the recording liquid without hindering effective transfer of the heat generated by the heat generating resistor 31 to the recording liquid. is there. Materials useful as the material of the protective layer 33 include, for example, silicon oxide, silicon nitride,
Magnesium oxide, aluminum oxide, tantalum oxide,
Examples thereof include zirconium oxide and the like, which can be formed by using a technique such as electron beam evaporation or sputtering. The thickness of the protective layer 33 is usually 0.01 to 10 μm,
It is preferably 0.1 to 5 μm, and most preferably 0.1 to 3 μm.

The recording head produced as described above is
When the recording liquid is supplied with a pressure that does not cause the recording liquid to be ejected from the ejection port when the heating resistor does not generate heat, recording is performed by applying a voltage in a pulsed manner to the electric / thermal converter according to the image signal. A clear image was obtained.

FIG. 7 is a block diagram showing an example of a heating element drive circuit at that time. Reference numeral 41 denotes a known optical input photosensor portion for reading, which is composed of a photodiode or the like. The image signal input to 41 is processed by the processing circuit 42 including a circuit such as a comparator, and input to the drive circuit 43. Drive circuit 43
Drives the recording head 44 by controlling the pulse width, pulse amplitude, repetition frequency, etc. according to the input signal. For example, in the simplest recording, the input image signal is processed by the processing circuit 4.
In 2 the black and white is discriminated and input to the drive circuit 43.
In the drive circuit 43, the pulse width and pulse amplitude for obtaining an appropriate droplet diameter and the repetition frequency for obtaining a desired recording droplet density are converted into a controlled signal to drive the recording head 44. Further, as another recording method considering the gradation, one is to perform recording with a changed droplet diameter, and another is to perform recording with a changed number of recording droplets as follows. You can also

First, in the recording method for changing the droplet diameter, the image signal input by the optical input photosensor section 41 is such that the pulse width and pulse amplitude of each level determined to obtain a desired droplet diameter. The processing circuit 42 determines and processes which level of the drive circuit 43 having a plurality of circuits for outputting the drive signal of which signal should output the signal. Further, in the method of changing the number of recording droplets, the input signal to the optical input photosensor unit 41 is A / D converted and output in the processing circuit 42, and the drive circuit 43 outputs one input signal according to the output signal. A signal for driving the recording head 44 is output so that recording is performed by changing the number of ejected droplets per hit. As another implementation method, a similar device is used to supply the recording liquid to the recording head 44 at a pressure higher than the recording liquid overflowing from the ejection port in a state where the heating resistor does not generate heat, and electrothermal conversion is performed. When recording was performed by applying a voltage to the body with continuous repeated pulses, it was confirmed that a number of droplets according to the applied frequency were stably ejected and ejected with a uniform diameter.

From this point, it was found that the recording head 44 is very effectively applied to continuous ejection at high frequency.
Further, since the recording head, which is a main part of the recording apparatus, is minute, a plurality of recording heads can be easily arranged, and a high-density multi-orifice recording head is possible.

FIG. 8 is a diagram for explaining another means for generating bubbles in the recording liquid. In the figure, 51 is a laser oscillator, 52 is a light modulation drive circuit, 53 is a light modulator, and 54 is a scanner. , 55 are condenser lenses, and the laser light generated from the laser oscillator 51 is pulse-modulated in the optical modulator 53 in accordance with an image information signal which is input to the optical modulator drive circuit 52, electrically processed, and output. To be done. The pulse-modulated laser light passes through the scanner 54 and is condensed by the condenser lens 55 so as to be focused on the outer wall of the thermal energy acting portion, heats the outer wall 56 of the recording head, and the inside of the recording liquid 57. To generate bubbles. Alternatively, the wall 56 of the thermal energy acting portion is made of a material that is transparent to the laser light, and is condensed by the condenser lens 55 so as to be focused on the recording liquid 57 inside, so that the recording liquid is directly heated. Bubbles may be generated by.

FIG. 9 is a view for explaining an example of the printer using the laser light as described above.
Shows an example in which they are integrated so as to be covered at a high density (for example, 8 nozzles / mmm) and over the entire paper width (for example, A4 width) of the paper 62. The laser light emitted from the laser oscillator 51 is guided to the entrance opening of the optical modulator 53. In the optical modulator 53, the laser light is modulated in intensity according to the image information input signal to the optical modulator 53. The modulated laser light has its optical path bent by the reflecting mirror 58 toward the beam expander 59,
It is incident on the beam expander 59. The beam expander 59 expands the beam diameter of the parallel light.
Next, the laser beam with the expanded beam diameter is incident on the rotary polygon mirror 60 that rotates at a constant speed at a high speed. The laser light swept by the rotating polygon mirror 60 is condensed by the condenser lens 55.
An image is formed on the outer wall 56 of the thermal energy acting portion of the drop generator or the recording liquid inside. As a result, bubbles are generated in each thermal energy acting portion, recording liquid droplets are ejected, and recording is performed on the recording paper 62.

FIG. 10 is a view showing still another bubble generating means. In this example, a pair of discharge electrodes 70 arranged on the inner wall side of the thermal energy acting portion sends a high voltage pulse from a discharge device 71. It receives a discharge in the recording liquid and instantly forms bubbles by the heat generated by the discharge.

11 to 18 are views showing specific examples of the discharge electrode shown in FIG. 10. In the example shown in FIG. 11, the electrode 70 is formed into a needle shape to concentrate the electric field and efficiently.
It is designed to cause a discharge (at low energy). In the example shown in FIG. 12, two flat plate electrodes are used so that bubbles can be stably generated between the electrodes. The position of the generated bubble is more stable than the needle-shaped electrode. FIG.
In the example shown in, the electrode is provided with a substantially coaxial hole. Both holes of the two electrodes serve as guides to further stabilize the position of the generated bubbles. The example shown in FIG. 14 is a ring-shaped electrode, which is basically the same as the example shown in FIG. 14 and is a modified example thereof. In the example shown in FIG. 15, one is a ring electrode and the other is a needle electrode. The ring-shaped electrode aims at the stability of the generated bubbles, and the needle-shaped electrode aims at the efficiency by concentrating the electric field. In the example shown in FIG. 16, one ring-shaped electrode is formed on the wall surface of the thermal energy acting portion. This aims at the manufacturing ease of forming the electrodes in a plane on the substrate, in addition to the effect of the example shown in FIG. A plurality of such high-density electrodes can be easily manufactured by a technique such as vapor deposition (or sputtering) or photoetching. Especially useful for multi-arrays. The example shown in FIG.
The ring-shaped electrode forming portion of the example shown in (1) is formed in a shape along the outer periphery of the electrode and is raised one step from the periphery. Again, this is aimed at the stability of the generated bubbles, and is more stable than that shown in FIG. 15 by the addition of a three-dimensional guide.

[0039]

As is apparent from the above description, according to the present invention, the relationship between the height ha of the liquid flow path and the height hb of the recording liquid chamber in the bubble jet type liquid jet recording head of the multi-nozzle array. And hb / ha> 2, and the maximum printable area of the head is 6 mm or more and 16 mm or less, or the driving frequency of the heating element is 3.2 kHz to 6.6 kHz.
By doing so, crosstalk between the flow paths is eliminated, and the ejection performance does not vary between the center and the end.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a main part for explaining an embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of a bubble jet head as an example of an inkjet head to which the present invention is applied.

FIG. 3 is a perspective view showing an example of a bubble jet head.

FIG. 4 is an exploded perspective view.

FIG. 5 is a view of the lid substrate as viewed from the back side.

FIG. 6 is a diagram for explaining the structure of a bubble generating means using a heating resistor.

FIG. 7 is a block diagram for explaining an example of a heating element drive circuit.

FIG. 8 is a diagram for explaining an example of a bubble generating means using laser light.

FIG. 9 is a diagram illustrating an example of a printer.

FIG. 10 is a diagram for explaining an example of a bubble generating unit that uses electric discharge.

11 is a diagram showing a specific example of the discharge electrode shown in FIG.

12 is a diagram showing a specific example of the discharge electrode shown in FIG.

13 is a diagram showing a specific example of the discharge electrode shown in FIG.

14 is a diagram showing a specific example of the discharge electrode shown in FIG.

15 is a diagram showing a specific example of the discharge electrode shown in FIG.

16 is a diagram showing a specific example of the discharge electrode shown in FIG.

FIG. 17 is a diagram showing a specific example of the discharge electrode shown in FIG.

18 is a diagram showing a specific example of the discharge electrode shown in FIG.

FIG. 19 is a diagram for explaining an example of a conventional technique.

[Explanation of symbols]

11 ... Lid substrate, 12 ... Heating element substrate, 14 ... Orifice,
15 ... Flow path, 16 ... Liquid chamber, 17, 18 ... Electrode, 19 ... Heating element, 20 ... Recording liquid, 21 ... Bubbles.

Claims (2)

[Claims] 1. A recording liquid chamber is connected to the recording liquid chamber, and the recording liquid introduced from the recording liquid chamber is contained therein. At the same time, bubbles are generated in the recording liquid by heat, and an action force is generated with an increase in the volume of the bubbles. A flow path provided with a thermal energy acting part, an orifice for communicating with the flow path to eject the recording liquid as a droplet by the acting force, and a recording liquid in the flow path for communicating with the flow path. In a liquid jet recording head comprising a recording liquid chamber for introducing the recording liquid and a means for introducing the recording liquid into the recording liquid chamber, the maximum printable area is 6 mm or more and 16 mm or less, and the height of the flow path is high. Where h is the height of the recording liquid chamber and hb is the height of the recording liquid chamber, the liquid jet recording head is characterized by satisfying a relationship of hb / ha> 2. 2. A recording liquid chamber is connected to the recording liquid chamber, and the recording liquid introduced from the recording liquid chamber is accommodated in the recording liquid chamber. At the same time, bubbles are generated in the recording liquid chamber by heat to generate an acting force associated with an increase in the volume of the bubbles. A flow path provided with a thermal energy acting part, an orifice for communicating with the flow path to eject the recording liquid as a droplet by the acting force, and a recording liquid in the flow path for communicating with the flow path. In a liquid jet recording head comprising a recording liquid chamber for introducing the recording liquid and a unit for introducing the recording liquid into the recording liquid chamber, the driving frequency of the heating element is 3.2 kHz to 6.6 kHz, and A liquid jet recording head, wherein a relationship of hb / ha> 2 is satisfied, where a flow path height is ha and a recording liquid chamber height is hb.